Stranger Things creators Matt and Ross Duffer are being sued by producer Charlie Kessler, who claims they ripped off his 2012 short film Montauk to make their blockbuster Netflix original series. The lawsuit was first reported by TMZ. Kessler produced the short film, which deals with secretive government experiments. The short premiered in 2012 and won a prize at the Hamptons International Film Festival.

According to the lawsuit, Kessler approached the Duffer brothers in 2014 with an idea to turn Montauk into a full-fledged television series. The talks never advanced beyond an idea pitch, in which the project was reportedly called The Montauk Project. Kessler says the brothers used his script, idea, and story to make Stranger Things.

The Netflix series premiered in July 2016 and has aired two season to date. Production on the third season of Stranger Things is expected to kick off this summer. IndieWire has reached out for comment from Netflix and representatives for the Duffer Brothers.

Montauk is available to stream on Vimeo. You can watch the short film below.